(a) Field of the Invention
This invention relates to pillar trims for motor vehicles fitted with airbags as safety measures in case of side collisions.
(b) Description of the Related Art
Various airbag systems for protecting motor vehicle passengers' heads in case of a side collision have been conventionally known. Among such airbag systems are known those in which an airbag is placed on the vehicle interior side of the side body of a motor vehicle and towards the roof to extend in a front-to-rear direction of the vehicle body from a front pillar (hereinafter, referred to as an A-pillar) through a center pillar (hereinafter, referred to as a B-pillar) to the vicinity of a rear pillar (hereinafter, referred to as a C-pillar), as disclosed, for example, in Published Japanese Patent Application No. 2002-59802 and Published Japanese Patent No. 3866733. In these known airbag systems, the airbag is contained between a pillar inner panel and a top sealing member so as to be covered from the vehicle interior side with the top sealing member.
In the above known airbag systems, a plurality of guide platforms are disposed, at an upper end part of a pillar trim body covering the interior side of each pillar, at spaced intervals in the front-to-rear direction of the vehicle body to rise up beyond the upper end of the pillar trim body. Each guide platform has a guide surface for guiding the inflation of the airbag towards the vehicle interior. The airbag is placed in a folded state on top of the guide platforms. The lower end of the top sealing member is connected to the upper end part of the pillar trim body. Upon inflation of the airbag, the airbag pushes open a lower part of the top sealing member towards the vehicle interior and is guided by the guide surfaces of the guide platforms to inflate towards the vehicle interior.
In the airbag system disclosed in Published Japanese Patent No. 3866733, the pillar trim body has bosses formed below the guide platform to rise towards the pillar of the vehicle body. The pillar trim body is fitted to the pillar by engaging clips at the distal ends of the bosses into clip holes formed in the pillar.
The guide platforms receive a reaction force upon inflation of the airbag. Therefore, to withstand the reaction force, the upper end part of the pillar trim body is generally given a high rigidity.
However, if the upper end part of the pillar trim body has a high rigidity, this causes a problem in safety that in case where the passenger's head hits the upper end part of the pillar trim body in a side collision, the passenger might be seriously damaged.
If each boss includes a clip as in Published Japanese Patent No. 3866733, upon action of a reaction force due to inflation of the airbag on the guide platforms, a force is transmitted from the pillar trim body to the boss located below the guide platforms. This might cause breakage of the boss from its basal end close to the pillar trim body.
Alternatively, unlike with the airbag system in which the boss includes a clip as in Published Japanese Patent No. 3866733, a technique is known in which the pillar trim body has a positioning pin formed below the guide platforms to rise therefrom for the purpose of positioning the pillar trim body in fitting it to the pillar. Also in this case, the positioning pin might break likewise upon inflation of the airbag.
Furthermore, in the structure in which a plurality of guide platforms are disposed at spaced intervals as in the above known airbag systems, the inflating airbag cannot be supported between the guide platforms. Therefore, its reaction force is concentrated on the guide platforms, which might break the guide platforms.
A first object of the present invention is to provide a motor vehicle pillar trim ensuring, in case of a side collision, an appropriate rigidity that can withstand a reaction force due to inflation of the airbag and passengers' safety.
A second object of the present invention is to prevent a positioning pin of a pillar trim body from breaking upon inflation of an airbag.
A third object of the present invention is to prevent guide platforms from being broken by a reaction force upon inflation of an airbag.